SUMMARY:In order to prepare porous beads with good characteristics mixtures of diluents were used. The influence of the ¶meter values of the two diluents was investigated which constitute the mixture of diluents on the macroporous features.The influence of the mixtures of 2-ethyl hexyl alcohoVpolystyrene @& = 172000), 2ethyl hexyl alcohol/toluene, and gasoline (bp 11 0 -125 "C)/polystyrene on the styrene-divinylbenzene macroporous copolymer features was investigated. It was found that the specific surface areas or the porosities of the macroporous copolymers were very sensitive to the modifications of the ¶meter values and the monomer composition.
ZUSAMMENFASSUNGEs wurden Mischungen von Verdiinnungsmitteln verwendet, um portjse Perlen mit guten Charakteristiken zu erhalten. So wurde der Einflu8 der &Parameter der beiden ftir die Mischung verwendeten Verdiinnungsmittel auf die Makroporosittltskennwerte untersucht.Der EinfluB der Mischungen von 2-Ethyl-hexylalkohol/Polystyrol (k = 172OOO), 2-Ethyl-hexylalkohol/Toluol und Benzin (Sdp. 110 -125 "C)/Polystyrol auf die Charakteristiken der makroportjsen Styrol-Divinylbenzol-Copolymeren wurde eingehend untersucht. Man stellte fest, da8 die spezifischen Oberfltlchen oder die Porosittlten der makroportjsen Copolymeren sehr empfindlich gegen die hderungen der &Para-meterwerte und der Zusammensetzung der Monomeren sind.
Crosslinked copolymers of acrylamide (AA) and ethylacrylate and some ion exchangers derived from them containing either primary amine groups, obtained by the Hofmann degradation of the amide groups, or carboxylic groups, obtained by the alkaline hydrolysis of the ester groups, were studied. Divinylbenzene and N,NЈ-methylenebisacrylamide were used as crosslinkers. The starting copolymers and the corresponding ion exchangers were characterized by IR spectroscopy, swelling behavior, and thermogravimetric analysis. The ion-exchanger properties were correlated with the crosslinker nature and the chemical reactions performed on the AA copolymers. The average molecular weight between two crosslinks, determined from the swelling data in water, was compared with that calculated on the basis of the copolymerization stoichiometry only for the carboxylic cation exchangers. In this way, the preservation of the crosslink density after the hydrolysis was revealed.
The influence of the removal of various diluents, pore forming agents from the porous styrene-ethylstyrene-acrylonitrile-divinylbenzene copolymers on the structure of the matrix was investigated by several methods. The most advantageous pathway to preserve the initial structural edifice of the porous networks performed in the presence of solvating diluents consisted in the removal of the inert media with methanol as it was noticed from the experimental data. If the steam treatment is applied, the collapse effect takes place and the anion exchangers prepared from such matrices exchange/adsorb less dye stuff by comparison with ones formed from beads treated with methanol, because the pore size was changed. It was also noticed that the porous copolymers performed in the presence of the solvating diluents (mixtures of solvatings and precipitants) swell very well in methanol though it is a precipitating medium for the polystyrenic macromolecular chains.
ZUSAMMENFASSUNG:Mit Hilfe verschiedener Methoden wurde der EinfluR der Entfernung unterschiedlicher porenbildender VerdUnner aus porOsen Styrol-Ethylstyrol-Acrylnitril-Divinylbenzol-Copolymeren auf die Netzwerkstruktur untersucht. Der gtinstigste Weg, den urspriinglichen strukturellen Bau des porOsen Netzwerkes zu bewahren, welches in Gegenwart von solvatisierenden Verdiinnern erhalten wurde, ist das Entfernen des inerten Mediums mit Methanol. Wenn die Wasserdampfmethode angewendet wird, findet der sog. Kollapseffekt statt, und die aus solchen Harzen hergestellten Anionenaustauscher adsorbieren weniger Farbstoff im Vergleich zu jenen, die aus Perlen hergestellt worden sind, die mit Methanol behandelt wurden; Grund hierfiir ist die durch den Kollaps verlnderte Porengr6De. Es wurde ebenfalls festgestellt, da8 die in Anwesenheit von solvatisierenden Verdiinnern (Mischungen aus Quellungs-und FBllmitteln) hergestellten Copolymeren in Methanol sehr gut quellen, obwohl dieses ein FBllungsmittel ftir Polystyrol ist.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.